Twist1 and Y-box-binding protein-1 are potential prognostic factors in bladder cancer

Objective: To investigate the expression and possible roles of Twist1 and Y-box-binding protein-1 (YB-1) in bladder cancer tissue. Twist1 belongs to the family of basic helix-loop-helix transcription factors. A functional link between Twist1 and YB-1 has recently been determined to play an important role in bladder cancer cell lines. Materials and methods: Frozen samples from 75 patients with bladder cancer were analyzed by quantitative real-time polymerase chain reaction (PCR). Formalin-fixed and paraffin-embedded tissues from 53 patients with bladder cancer were examined by immunohistochemistry. Results: Twist1 transcript levels were positively correlated with YB-1 transcript levels (coefficient of correlation = 0.42, P<0.001), tumor grade (low grade vs. high grade; P<0.001), invasiveness (non-muscle-invasive bladder cancer vs. muscle invasive bladder cancer; P = 0.0018), and metastasis (meta- vs. meta+; P<0.001). YB-1 transcript level was also correlated with grade (P = 0.029) and invasiveness (P = 0.006). By immunohistochemistry, Twist1 expression was also correlated with YB-1 expression (P<0.001). Further, both Twist1 and YB-1 expression were positively correlated with invasiveness (P = 0.007 and P = 0.002, respectively). Patients with high Twist1 expression and high YB-1 expression had lower overall survival rates, compared with patients with low expression (log-rank test, P = 0.040 and P<0.001, respectively). Conclusions: These results suggest a functional link between Twist1 and YB-1, and they indicate that Twist1 and YB-1 promote bladder cancer progression.